diff --git a/Cargo.lock b/Cargo.lock
index 8a4c893..17aa891 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -41,6 +41,56 @@ dependencies = [
  "libc",
 ]
 
+[[package]]
+name = "anstream"
+version = "0.6.21"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "43d5b281e737544384e969a5ccad3f1cdd24b48086a0fc1b2a5262a26b8f4f4a"
+dependencies = [
+ "anstyle",
+ "anstyle-parse",
+ "anstyle-query",
+ "anstyle-wincon",
+ "colorchoice",
+ "is_terminal_polyfill",
+ "utf8parse",
+]
+
+[[package]]
+name = "anstyle"
+version = "1.0.13"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5192cca8006f1fd4f7237516f40fa183bb07f8fbdfedaa0036de5ea9b0b45e78"
+
+[[package]]
+name = "anstyle-parse"
+version = "0.2.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4e7644824f0aa2c7b9384579234ef10eb7efb6a0deb83f9630a49594dd9c15c2"
+dependencies = [
+ "utf8parse",
+]
+
+[[package]]
+name = "anstyle-query"
+version = "1.1.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "40c48f72fd53cd289104fc64099abca73db4166ad86ea0b4341abe65af83dadc"
+dependencies = [
+ "windows-sys 0.61.2",
+]
+
+[[package]]
+name = "anstyle-wincon"
+version = "3.0.11"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "291e6a250ff86cd4a820112fb8898808a366d8f9f58ce16d1f538353ad55747d"
+dependencies = [
+ "anstyle",
+ "once_cell_polyfill",
+ "windows-sys 0.61.2",
+]
+
 [[package]]
 name = "anyhow"
 version = "1.0.101"
@@ -234,6 +284,21 @@ dependencies = [
  "serde",
 ]
 
+[[package]]
+name = "bit-set"
+version = "0.8.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "08807e080ed7f9d5433fa9b275196cfc35414f66a0c79d864dc51a0d825231a3"
+dependencies = [
+ "bit-vec",
+]
+
+[[package]]
+name = "bit-vec"
+version = "0.8.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5e764a1d40d510daf35e07be9eb06e75770908c27d411ee6c92109c9840eaaf7"
+
 [[package]]
 name = "bitflags"
 version = "1.3.2"
@@ -280,6 +345,31 @@ dependencies = [
  "piper",
 ]
 
+[[package]]
+name = "bon"
+version = "3.9.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2d13a61f2963b88eef9c1be03df65d42f6996dfeac1054870d950fcf66686f83"
+dependencies = [
+ "bon-macros",
+ "rustversion",
+]
+
+[[package]]
+name = "bon-macros"
+version = "3.9.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d314cc62af2b6b0c65780555abb4d02a03dd3b799cd42419044f0c38d99738c0"
+dependencies = [
+ "darling",
+ "ident_case",
+ "prettyplease",
+ "proc-macro2",
+ "quote",
+ "rustversion",
+ "syn 2.0.116",
+]
+
 [[package]]
 name = "brotli"
 version = "8.0.2"
@@ -395,6 +485,15 @@ dependencies = [
  "toml 0.9.12+spec-1.1.0",
 ]
 
+[[package]]
+name = "caseless"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8b6fd507454086c8edfd769ca6ada439193cdb209c7681712ef6275cccbfe5d8"
+dependencies = [
+ "unicode-normalization",
+]
+
 [[package]]
 name = "cc"
 version = "1.2.56"
@@ -452,6 +551,53 @@ dependencies = [
  "windows-link 0.2.1",
 ]
 
+[[package]]
+name = "clap"
+version = "4.5.58"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "63be97961acde393029492ce0be7a1af7e323e6bae9511ebfac33751be5e6806"
+dependencies = [
+ "clap_builder",
+ "clap_derive",
+]
+
+[[package]]
+name = "clap_builder"
+version = "4.5.58"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7f13174bda5dfd69d7e947827e5af4b0f2f94a4a3ee92912fba07a66150f21e2"
+dependencies = [
+ "anstream",
+ "anstyle",
+ "clap_lex",
+ "strsim",
+ "terminal_size",
+]
+
+[[package]]
+name = "clap_derive"
+version = "4.5.55"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a92793da1a46a5f2a02a6f4c46c6496b28c43638adea8306fcb0caa1634f24e5"
+dependencies = [
+ "heck 0.5.0",
+ "proc-macro2",
+ "quote",
+ "syn 2.0.116",
+]
+
+[[package]]
+name = "clap_lex"
+version = "1.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3a822ea5bc7590f9d40f1ba12c0dc3c2760f3482c6984db1573ad11031420831"
+
+[[package]]
+name = "colorchoice"
+version = "1.0.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b05b61dc5112cbb17e4b6cd61790d9845d13888356391624cbe7e41efeac1e75"
+
 [[package]]
 name = "combine"
 version = "4.6.7"
@@ -462,6 +608,30 @@ dependencies = [
  "memchr",
 ]
 
+[[package]]
+name = "comrak"
+version = "0.50.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "321d20bf105b6871a49da44c5fbb93e90a7cd6178ea5a9fe6cbc1e6d4504bc5e"
+dependencies = [
+ "bon",
+ "caseless",
+ "clap",
+ "emojis",
+ "entities",
+ "fmt2io",
+ "jetscii",
+ "phf 0.13.1",
+ "phf_codegen 0.13.1",
+ "rustc-hash",
+ "shell-words",
+ "smallvec",
+ "syntect",
+ "typed-arena",
+ "unicode_categories",
+ "xdg",
+]
+
 [[package]]
 name = "concurrent-queue"
 version = "2.5.0"
@@ -804,12 +974,27 @@ version = "1.2.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "4ef6b89e5b37196644d8796de5268852ff179b44e96276cf4290264843743bb7"
 
+[[package]]
+name = "emojis"
+version = "0.8.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "50c1c1870b766fc398e5f0526498d09c94b6de15be5fd769a28bbc804fb1b05d"
+dependencies = [
+ "phf 0.13.1",
+]
+
 [[package]]
 name = "endi"
 version = "1.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "66b7e2430c6dff6a955451e2cfc438f09cea1965a9d6f87f7e3b90decc014099"
 
+[[package]]
+name = "entities"
+version = "1.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b5320ae4c3782150d900b79807611a59a99fc9a1d61d686faafc24b93fc8d7ca"
+
 [[package]]
 name = "enumflags2"
 version = "0.7.12"
@@ -891,6 +1076,17 @@ version = "0.1.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7360491ce676a36bf9bb3c56c1aa791658183a54d2744120f27285738d90465a"
 
+[[package]]
+name = "fancy-regex"
+version = "0.16.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "998b056554fbe42e03ae0e152895cd1a7e1002aec800fdc6635d20270260c46f"
+dependencies = [
+ "bit-set",
+ "regex-automata",
+ "regex-syntax",
+]
+
 [[package]]
 name = "fastrand"
 version = "2.3.0"
@@ -932,6 +1128,12 @@ dependencies = [
  "miniz_oxide",
 ]
 
+[[package]]
+name = "fmt2io"
+version = "1.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6b6129284da9f7e5296cc22183a63f24300e945e297705dcc0672f7df01d62c8"
+
 [[package]]
 name = "fnv"
 version = "1.0.7"
@@ -1760,6 +1962,12 @@ dependencies = [
  "once_cell",
 ]
 
+[[package]]
+name = "is_terminal_polyfill"
+version = "1.70.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a6cb138bb79a146c1bd460005623e142ef0181e3d0219cb493e02f7d08a35695"
+
 [[package]]
 name = "itoa"
 version = "1.0.17"
@@ -1789,6 +1997,12 @@ dependencies = [
  "system-deps",
 ]
 
+[[package]]
+name = "jetscii"
+version = "0.5.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "47f142fe24a9c9944451e8349de0a56af5f3e7226dc46f3ed4d4ecc0b85af75e"
+
 [[package]]
 name = "jni"
 version = "0.21.1"
@@ -1939,6 +2153,12 @@ dependencies = [
  "vcpkg",
 ]
 
+[[package]]
+name = "linked-hash-map"
+version = "0.5.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0717cef1bc8b636c6e1c1bbdefc09e6322da8a9321966e8928ef80d20f7f770f"
+
 [[package]]
 name = "linux-raw-sys"
 version = "0.11.0"
@@ -2363,6 +2583,34 @@ version = "1.21.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "42f5e15c9953c5e4ccceeb2e7382a716482c34515315f7b03532b8b4e8393d2d"
 
+[[package]]
+name = "once_cell_polyfill"
+version = "1.70.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "384b8ab6d37215f3c5301a95a4accb5d64aa607f1fcb26a11b5303878451b4fe"
+
+[[package]]
+name = "onig"
+version = "6.5.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "336b9c63443aceef14bea841b899035ae3abe89b7c486aaf4c5bd8aafedac3f0"
+dependencies = [
+ "bitflags 2.11.0",
+ "libc",
+ "once_cell",
+ "onig_sys",
+]
+
+[[package]]
+name = "onig_sys"
+version = "69.9.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c7f86c6eef3d6df15f23bcfb6af487cbd2fed4e5581d58d5bf1f5f8b7f6727dc"
+dependencies = [
+ "cc",
+ "pkg-config",
+]
+
 [[package]]
 name = "open"
 version = "5.3.3"
@@ -2487,6 +2735,16 @@ dependencies = [
  "phf_shared 0.11.3",
 ]
 
+[[package]]
+name = "phf"
+version = "0.13.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c1562dc717473dbaa4c1f85a36410e03c047b2e7df7f45ee938fbef64ae7fadf"
+dependencies = [
+ "phf_shared 0.13.1",
+ "serde",
+]
+
 [[package]]
 name = "phf_codegen"
 version = "0.8.0"
@@ -2507,6 +2765,16 @@ dependencies = [
  "phf_shared 0.11.3",
 ]
 
+[[package]]
+name = "phf_codegen"
+version = "0.13.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "49aa7f9d80421bca176ca8dbfebe668cc7a2684708594ec9f3c0db0805d5d6e1"
+dependencies = [
+ "phf_generator 0.13.1",
+ "phf_shared 0.13.1",
+]
+
 [[package]]
 name = "phf_generator"
 version = "0.8.0"
@@ -2537,6 +2805,16 @@ dependencies = [
  "rand 0.8.5",
 ]
 
+[[package]]
+name = "phf_generator"
+version = "0.13.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "135ace3a761e564ec88c03a77317a7c6b80bb7f7135ef2544dbe054243b89737"
+dependencies = [
+ "fastrand",
+ "phf_shared 0.13.1",
+]
+
 [[package]]
 name = "phf_macros"
 version = "0.10.0"
@@ -2591,6 +2869,15 @@ dependencies = [
  "siphasher 1.0.2",
 ]
 
+[[package]]
+name = "phf_shared"
+version = "0.13.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e57fef6bc5981e38c2ce2d63bfa546861309f875b8a75f092d1d54ae2d64f266"
+dependencies = [
+ "siphasher 1.0.2",
+]
+
 [[package]]
 name = "pin-project-lite"
 version = "0.2.16"
@@ -3033,6 +3320,12 @@ dependencies = [
  "sqlite-wasm-rs",
 ]
 
+[[package]]
+name = "rustc-hash"
+version = "2.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "357703d41365b4b27c590e3ed91eabb1b663f07c4c084095e60cbed4362dff0d"
+
 [[package]]
 name = "rustc_version"
 version = "0.4.1"
@@ -3324,6 +3617,12 @@ dependencies = [
  "digest",
 ]
 
+[[package]]
+name = "shell-words"
+version = "1.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "dc6fe69c597f9c37bfeeeeeb33da3530379845f10be461a66d16d03eca2ded77"
+
 [[package]]
 name = "shlex"
 version = "1.3.0"
@@ -3530,6 +3829,28 @@ dependencies = [
  "syn 2.0.116",
 ]
 
+[[package]]
+name = "syntect"
+version = "5.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "656b45c05d95a5704399aeef6bd0ddec7b2b3531b7c9e900abbf7c4d2190c925"
+dependencies = [
+ "bincode",
+ "fancy-regex",
+ "flate2",
+ "fnv",
+ "once_cell",
+ "onig",
+ "plist",
+ "regex-syntax",
+ "serde",
+ "serde_derive",
+ "serde_json",
+ "thiserror 2.0.18",
+ "walkdir",
+ "yaml-rust",
+]
+
 [[package]]
 name = "system-deps"
 version = "6.2.2"
@@ -3950,6 +4271,16 @@ dependencies = [
  "utf-8",
 ]
 
+[[package]]
+name = "terminal_size"
+version = "0.4.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "60b8cb979cb11c32ce1603f8137b22262a9d131aaa5c37b5678025f22b8becd0"
+dependencies = [
+ "rustix",
+ "windows-sys 0.60.2",
+]
+
 [[package]]
 name = "thiserror"
 version = "1.0.69"
@@ -4031,6 +4362,21 @@ dependencies = [
  "zerovec",
 ]
 
+[[package]]
+name = "tinyvec"
+version = "1.10.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bfa5fdc3bce6191a1dbc8c02d5c8bffcf557bafa17c124c5264a458f1b0613fa"
+dependencies = [
+ "tinyvec_macros",
+]
+
+[[package]]
+name = "tinyvec_macros"
+version = "0.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1f3ccbac311fea05f86f61904b462b55fb3df8837a366dfc601a0161d0532f20"
+
 [[package]]
 name = "tokio"
 version = "1.49.0"
@@ -4270,6 +4616,12 @@ version = "0.2.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e421abadd41a4225275504ea4d6566923418b7f05506fbc9c0fe86ba7396114b"
 
+[[package]]
+name = "typed-arena"
+version = "2.0.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6af6ae20167a9ece4bcb41af5b80f8a1f1df981f6391189ce00fd257af04126a"
+
 [[package]]
 name = "typeid"
 version = "1.0.3"
@@ -4340,6 +4692,15 @@ version = "1.0.23"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "537dd038a89878be9b64dd4bd1b260315c1bb94f4d784956b81e27a088d9a09e"
 
+[[package]]
+name = "unicode-normalization"
+version = "0.1.25"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5fd4f6878c9cb28d874b009da9e8d183b5abc80117c40bbd187a1fde336be6e8"
+dependencies = [
+ "tinyvec",
+]
+
 [[package]]
 name = "unicode-segmentation"
 version = "1.12.0"
@@ -4352,6 +4713,12 @@ version = "0.2.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "ebc1c04c71510c7f702b52b7c350734c9ff1295c464a03335b00bb84fc54f853"
 
+[[package]]
+name = "unicode_categories"
+version = "0.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "39ec24b3121d976906ece63c9daad25b85969647682eee313cb5779fdd69e14e"
+
 [[package]]
 name = "url"
 version = "2.5.8"
@@ -4389,6 +4756,12 @@ version = "1.0.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "b6c140620e7ffbb22c2dee59cafe6084a59b5ffc27a8859a5f0d494b5d52b6be"
 
+[[package]]
+name = "utf8parse"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "06abde3611657adf66d383f00b093d7faecc7fa57071cce2578660c9f1010821"
+
 [[package]]
 name = "uuid"
 version = "1.21.0"
@@ -5261,6 +5634,13 @@ dependencies = [
 [[package]]
 name = "writer-md"
 version = "0.1.0"
+dependencies = [
+ "comrak",
+ "serde",
+ "serde_json",
+ "thiserror 2.0.18",
+ "writer-core",
+]
 
 [[package]]
 name = "writer-store"
@@ -5343,6 +5723,21 @@ dependencies = [
  "pkg-config",
 ]
 
+[[package]]
+name = "xdg"
+version = "3.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2fb433233f2df9344722454bc7e96465c9d03bff9d77c248f9e7523fe79585b5"
+
+[[package]]
+name = "yaml-rust"
+version = "0.4.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "56c1936c4cc7a1c9ab21a1ebb602eb942ba868cbd44a99cb7cdc5892335e1c85"
+dependencies = [
+ "linked-hash-map",
+]
+
 [[package]]
 name = "yoke"
 version = "0.8.1"
diff --git a/crates/core/src/lib.rs b/crates/core/src/lib.rs
index aaa6f16..a7f4746 100644
--- a/crates/core/src/lib.rs
+++ b/crates/core/src/lib.rs
@@ -51,8 +51,7 @@ pub struct DocMeta {
 }
 
 /// File encoding detection and preservation
-#[derive(Debug, Clone, Copy, Serialize, Deserialize, PartialEq, Eq)]
-#[derive(Default)]
+#[derive(Debug, Clone, Copy, Serialize, Deserialize, PartialEq, Eq, Default)]
 pub enum Encoding {
     #[default]
     Utf8,
@@ -61,10 +60,8 @@ pub enum Encoding {
     Utf16Be,
 }
 
-
 /// Line ending style preservation
-#[derive(Debug, Clone, Copy, Serialize, Deserialize, PartialEq, Eq)]
-#[derive(Default)]
+#[derive(Debug, Clone, Copy, Serialize, Deserialize, PartialEq, Eq, Default)]
 pub enum LineEnding {
     #[default]
     Lf,
@@ -72,7 +69,6 @@ pub enum LineEnding {
     Auto,
 }
 
-
 /// Document content with metadata for opening
 #[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
 pub struct DocContent {
@@ -99,18 +95,15 @@ pub enum DocSortField {
 }
 
 /// Sort order
-#[derive(Debug, Clone, Copy, Serialize, Deserialize, PartialEq)]
-#[derive(Default)]
+#[derive(Debug, Clone, Copy, Serialize, Deserialize, PartialEq, Default)]
 pub enum SortOrder {
     Ascending,
     #[default]
     Descending,
 }
 
-
 /// Save policy options
-#[derive(Debug, Clone, Copy, Serialize, Deserialize, PartialEq)]
-#[derive(Default)]
+#[derive(Debug, Clone, Copy, Serialize, Deserialize, PartialEq, Default)]
 pub enum SavePolicy {
     /// Atomic save: write to temp, fsync, rename
     #[default]
@@ -119,7 +112,6 @@ pub enum SavePolicy {
     InPlace,
 }
 
-
 /// Result of a save operation
 #[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
 pub struct SaveResult {
diff --git a/crates/markdown/Cargo.toml b/crates/markdown/Cargo.toml
index bca7555..02b0ba3 100644
--- a/crates/markdown/Cargo.toml
+++ b/crates/markdown/Cargo.toml
@@ -4,3 +4,10 @@ version = "0.1.0"
 edition = "2024"
 
 [dependencies]
+writer-core = { path = "../core" }
+comrak = "0.50"
+serde = { version = "1", features = ["derive"] }
+thiserror = "2"
+
+[dev-dependencies]
+serde_json = "1"
diff --git a/crates/markdown/src/lib.rs b/crates/markdown/src/lib.rs
index b93cf3f..d371860 100644
--- a/crates/markdown/src/lib.rs
+++ b/crates/markdown/src/lib.rs
@@ -1,14 +1,444 @@
-pub fn add(left: u64, right: u64) -> u64 {
-    left + right
+use comrak::{Arena, Options, parse_document};
+use serde::{Deserialize, Serialize};
+
+/// Markdown rendering profiles defining feature sets and safety levels
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize, Default)]
+pub enum MarkdownProfile {
+    /// Strict CommonMark with no extensions
+    StrictCommonMark,
+    /// GitHub Flavored Markdown with safety features
+    /// Enables: tables, task lists, strikethrough, autolinks
+    /// Disables: raw HTML (treated as untrusted)
+    #[default]
+    GfmSafe,
+}
+
+impl MarkdownProfile {
+    /// Converts the profile to Comrak options
+    pub fn to_options(&self) -> Options<'_> {
+        match self {
+            MarkdownProfile::StrictCommonMark => Options {
+                extension: comrak::options::Extension { ..Default::default() },
+                parse: comrak::options::Parse::default(),
+                render: comrak::options::Render { r#unsafe: false, sourcepos: true, ..Default::default() },
+            },
+            MarkdownProfile::GfmSafe => Options {
+                extension: comrak::options::Extension {
+                    strikethrough: true,
+                    tagfilter: true,
+                    table: true,
+                    autolink: true,
+                    tasklist: true,
+                    superscript: false,
+                    header_ids: None,
+                    footnotes: false,
+                    description_lists: false,
+                    front_matter_delimiter: None,
+                    multiline_block_quotes: false,
+                    math_dollars: false,
+                    math_code: false,
+                    wikilinks_title_before_pipe: false,
+                    wikilinks_title_after_pipe: false,
+                    underline: false,
+                    subscript: false,
+                    spoiler: false,
+                    greentext: false,
+                    ..Default::default()
+                },
+                parse: comrak::options::Parse::default(),
+                render: comrak::options::Render { r#unsafe: false, sourcepos: true, ..Default::default() },
+            },
+        }
+    }
+}
+
+/// A heading in the document outline
+#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
+pub struct Heading {
+    pub level: u8,
+    pub text: String,
+    pub anchor: Option<String>,
+}
+
+/// Extracted document metadata from Markdown parsing
+#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
+pub struct DocumentMetadata {
+    /// Title extracted from first H1 heading
+    pub title: Option<String>,
+    /// Document outline (all headings H1-H6)
+    pub outline: Vec<Heading>,
+    /// All link references found in the document
+    pub links: Vec<LinkRef>,
+    /// Number of task list items (checked and unchecked)
+    pub task_items: TaskStats,
+    /// Estimated word count
+    pub word_count: usize,
+}
+
+/// Statistics about task list items
+#[derive(Debug, Clone, PartialEq, Eq, Default, Serialize, Deserialize)]
+pub struct TaskStats {
+    pub total: usize,
+    pub completed: usize,
+}
+
+/// A link reference found in the document
+#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
+pub struct LinkRef {
+    pub url: String,
+    pub title: Option<String>,
+}
+
+/// Result of rendering Markdown to HTML with metadata
+#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
+pub struct RenderResult {
+    /// The rendered HTML output
+    pub html: String,
+    /// Document metadata extracted during rendering
+    pub metadata: DocumentMetadata,
+}
+
+/// Errors that can occur during Markdown processing
+#[derive(Debug, Clone, thiserror::Error, PartialEq, Eq)]
+pub enum MarkdownError {
+    #[error("Failed to parse markdown: {0}")]
+    ParseError(String),
+}
+
+/// The main Markdown engine for parsing and rendering
+pub struct MarkdownEngine;
+
+impl MarkdownEngine {
+    /// Creates a new Markdown engine
+    pub fn new() -> Self {
+        Self
+    }
+
+    /// Renders Markdown text to HTML using the specified profile
+    ///
+    /// # Arguments
+    /// * `text` - The Markdown text to render
+    /// * `profile` - The rendering profile to use
+    ///
+    /// # Returns
+    /// A `RenderResult` containing the HTML and extracted metadata
+    pub fn render(&self, text: &str, profile: MarkdownProfile) -> Result<RenderResult, MarkdownError> {
+        let arena = Arena::new();
+        let options = profile.to_options();
+
+        let root = parse_document(&arena, text, &options);
+
+        let mut metadata = DocumentMetadata {
+            title: None,
+            outline: Vec::new(),
+            links: Vec::new(),
+            task_items: TaskStats::default(),
+            word_count: 0,
+        };
+
+        Self::extract_metadata_from_node(&root, &mut metadata, &mut true);
+
+        metadata.word_count = Self::estimate_word_count(text);
+
+        let mut html_output = String::new();
+        comrak::format_html(root, &options, &mut html_output).map_err(|e| MarkdownError::ParseError(e.to_string()))?;
+
+        Ok(RenderResult { html: html_output, metadata })
+    }
+
+    /// Renders Markdown using the default GfmSafe profile
+    pub fn render_default(&self, text: &str) -> Result<RenderResult, MarkdownError> {
+        self.render(text, MarkdownProfile::default())
+    }
+
+    /// Extracts metadata by traversing the AST
+    fn extract_metadata_from_node(node: &comrak::nodes::Node, metadata: &mut DocumentMetadata, first_h1: &mut bool) {
+        use comrak::nodes::NodeValue;
+
+        match &node.data.borrow().value {
+            NodeValue::Heading(heading) => {
+                let level = heading.level;
+                let text = Self::extract_text_from_node(node);
+
+                if level == 1 && *first_h1 {
+                    metadata.title = Some(text.clone());
+                    *first_h1 = false;
+                }
+
+                metadata.outline.push(Heading { level, text, anchor: None });
+            }
+            NodeValue::Link(link) => {
+                metadata.links.push(LinkRef {
+                    url: link.url.clone(),
+                    title: if link.title.is_empty() { None } else { Some(link.title.clone()) },
+                });
+            }
+            NodeValue::TaskItem(task_item) => {
+                metadata.task_items.total += 1;
+                if let Some(symbol) = task_item.symbol
+                    && (symbol == 'x' || symbol == 'X')
+                {
+                    metadata.task_items.completed += 1;
+                }
+            }
+            _ => {}
+        }
+
+        for child in node.children() {
+            Self::extract_metadata_from_node(&child, metadata, first_h1);
+        }
+    }
+
+    /// Extracts plain text from a node and its children
+    fn extract_text_from_node(node: &comrak::nodes::Node) -> String {
+        use comrak::nodes::NodeValue;
+
+        let mut text = String::new();
+
+        match &node.data.borrow().value {
+            NodeValue::Text(t) => {
+                text.push_str(t);
+            }
+            NodeValue::Code(code) => {
+                text.push_str(&code.literal);
+            }
+            _ => {
+                for child in node.children() {
+                    text.push_str(&Self::extract_text_from_node(&child));
+                }
+            }
+        }
+
+        text
+    }
+
+    /// Estimates word count from Markdown text
+    ///
+    /// This is a simple estimation that counts whitespace-separated tokens
+    fn estimate_word_count(text: &str) -> usize {
+        text.split_whitespace().filter(|s| !s.is_empty()).count()
+    }
+
+    /// Validates that HTML output contains source position attributes
+    ///
+    /// This is useful for testing that sourcepos is enabled
+    pub fn has_sourcepos(html: &str) -> bool {
+        html.contains("data-sourcepos")
+    }
+}
+
+impl Default for MarkdownEngine {
+    fn default() -> Self {
+        Self::new()
+    }
 }
 
 #[cfg(test)]
 mod tests {
     use super::*;
+    use std::fs;
+    use std::path::PathBuf;
+
+    #[test]
+    fn test_gfm_safe_blocks_raw_html() {
+        let engine = MarkdownEngine::new();
+        let markdown = "<script>alert('xss')</script>\n\nHello world";
+        let result = engine.render(markdown, MarkdownProfile::GfmSafe).unwrap();
+
+        assert!(!result.html.contains("<script>"));
+        assert!(!result.html.contains("alert"));
+    }
 
     #[test]
-    fn it_works() {
-        let result = add(2, 2);
-        assert_eq!(result, 4);
+    fn test_strict_common_mark_basic() {
+        let engine = MarkdownEngine::new();
+        let markdown = "# Hello\n\nThis is a paragraph.";
+        let result = engine.render(markdown, MarkdownProfile::StrictCommonMark).unwrap();
+
+        assert!(result.html.contains("<h1"));
+        assert!(result.html.contains("Hello"));
+        assert!(result.metadata.title == Some("Hello".to_string()));
+    }
+
+    #[test]
+    fn test_gfm_tables() {
+        let engine = MarkdownEngine::new();
+        let markdown = "| A | B |\n|---|---|\n| 1 | 2 |";
+        let result = engine.render(markdown, MarkdownProfile::GfmSafe).unwrap();
+
+        assert!(result.html.contains("<table"));
+    }
+
+    #[test]
+    fn test_gfm_task_lists() {
+        let engine = MarkdownEngine::new();
+        let markdown = "- [x] Done\n- [ ] Not done";
+        let result = engine.render(markdown, MarkdownProfile::GfmSafe).unwrap();
+
+        assert_eq!(result.metadata.task_items.total, 2);
+        assert_eq!(result.metadata.task_items.completed, 1);
+    }
+
+    #[test]
+    fn test_sourcepos_present() {
+        let engine = MarkdownEngine::new();
+        let markdown = "# Hello\n\nParagraph here.";
+        let result = engine.render(markdown, MarkdownProfile::GfmSafe).unwrap();
+
+        assert!(MarkdownEngine::has_sourcepos(&result.html));
+        assert!(result.html.contains("data-sourcepos"));
+    }
+
+    #[test]
+    fn test_outline_extraction() {
+        let engine = MarkdownEngine::new();
+        let markdown = "# Title\n\n## Section 1\n\n### Subsection\n\n## Section 2";
+        let result = engine.render(markdown, MarkdownProfile::GfmSafe).unwrap();
+
+        assert_eq!(result.metadata.outline.len(), 4);
+        assert_eq!(result.metadata.outline[0].level, 1);
+        assert_eq!(result.metadata.outline[0].text, "Title");
+        assert_eq!(result.metadata.outline[1].level, 2);
+        assert_eq!(result.metadata.outline[1].text, "Section 1");
+    }
+
+    #[test]
+    fn test_word_count() {
+        let engine = MarkdownEngine::new();
+        let markdown = "This has five words total.";
+        let result = engine.render(markdown, MarkdownProfile::GfmSafe).unwrap();
+
+        assert_eq!(result.metadata.word_count, 5);
+    }
+
+    #[test]
+    fn test_strikethrough() {
+        let engine = MarkdownEngine::new();
+        let markdown = "~~deleted~~";
+        let result = engine.render(markdown, MarkdownProfile::GfmSafe).unwrap();
+
+        assert!(result.html.contains("<del") || result.html.contains("<s>"));
+    }
+
+    #[test]
+    fn test_autolinks() {
+        let engine = MarkdownEngine::new();
+        let markdown = "Visit https://example.com for info";
+        let result = engine.render(markdown, MarkdownProfile::GfmSafe).unwrap();
+
+        assert!(result.html.contains("<a ") || result.html.contains("<a>"));
+        assert!(result.html.contains("href="));
+        assert!(result.html.contains("example.com"));
+    }
+
+    fn fixtures_dir() -> PathBuf {
+        PathBuf::from(env!("CARGO_MANIFEST_DIR"))
+            .join("..")
+            .join("..")
+            .join("fixtures")
+            .join("markdown")
+    }
+
+    fn render_fixtures_dir() -> PathBuf {
+        PathBuf::from(env!("CARGO_MANIFEST_DIR"))
+            .join("..")
+            .join("..")
+            .join("fixtures")
+            .join("render")
+    }
+
+    #[test]
+    fn test_golden_basic_markdown() {
+        let engine = MarkdownEngine::new();
+        let fixtures = fixtures_dir();
+        let markdown = fs::read_to_string(fixtures.join("basic.md")).expect("Failed to read basic.md");
+        let expected_html = fs::read_to_string(fixtures.join("basic.html")).expect("Failed to read basic.html");
+        let result = engine.render(&markdown, MarkdownProfile::GfmSafe).unwrap();
+        let actual_html = result.html.trim();
+        let expected_html = expected_html.trim();
+        assert_eq!(
+            actual_html, expected_html,
+            "HTML output does not match expected fixture"
+        );
+    }
+
+    #[test]
+    fn test_golden_basic_outline() {
+        let engine = MarkdownEngine::new();
+        let fixtures = fixtures_dir();
+        let markdown = fs::read_to_string(fixtures.join("basic.md")).expect("Failed to read basic.md");
+        let result = engine.render(&markdown, MarkdownProfile::GfmSafe).unwrap();
+        assert_eq!(result.metadata.title, Some("Test Document".to_string()));
+        assert_eq!(result.metadata.outline.len(), 4);
+        assert_eq!(result.metadata.outline[0].level, 1);
+        assert_eq!(result.metadata.outline[0].text, "Test Document");
+        assert_eq!(result.metadata.outline[1].level, 2);
+        assert_eq!(result.metadata.outline[1].text, "Section 1");
+        assert_eq!(result.metadata.outline[2].level, 3);
+        assert_eq!(result.metadata.outline[2].text, "Subsection");
+        assert_eq!(result.metadata.outline[3].level, 2);
+        assert_eq!(result.metadata.outline[3].text, "Section 2");
+    }
+
+    #[test]
+    fn test_golden_basic_task_stats() {
+        let engine = MarkdownEngine::new();
+        let fixtures = fixtures_dir();
+        let markdown = fs::read_to_string(fixtures.join("basic.md")).expect("Failed to read basic.md");
+        let result = engine.render(&markdown, MarkdownProfile::GfmSafe).unwrap();
+        assert_eq!(result.metadata.task_items.total, 2);
+        assert_eq!(result.metadata.task_items.completed, 1);
+    }
+
+    #[test]
+    fn test_golden_sourcepos_present_in_fixture() {
+        let engine = MarkdownEngine::new();
+        let fixtures = fixtures_dir();
+        let markdown = fs::read_to_string(fixtures.join("basic.md")).expect("Failed to read basic.md");
+        let result = engine.render(&markdown, MarkdownProfile::GfmSafe).unwrap();
+        assert!(
+            result.html.contains("data-sourcepos"),
+            "Expected data-sourcepos attributes in output"
+        );
+
+        let block_elements = ["<h1", "<h2", "<h3", "<p", "<ul", "<li", "<table", "<pre"];
+        for element in &block_elements {
+            if result.html.contains(element) {
+                let pattern = format!("{} data-sourcepos=", element);
+                assert!(
+                    result.html.contains(&pattern),
+                    "Expected {} to have data-sourcepos attribute",
+                    element
+                );
+            }
+        }
+    }
+
+    #[test]
+    fn test_golden_xss_safety() {
+        let engine = MarkdownEngine::new();
+        let fixtures = render_fixtures_dir();
+
+        let markdown = fs::read_to_string(fixtures.join("xss-safety.md")).expect("Failed to read xss-safety.md");
+        let expected_html =
+            fs::read_to_string(fixtures.join("xss-safety.html")).expect("Failed to read xss-safety.html");
+
+        let result = engine.render(&markdown, MarkdownProfile::GfmSafe).unwrap();
+
+        assert!(
+            !result.html.contains("<script>"),
+            "Script tags should be escaped or removed"
+        );
+        assert!(
+            !result.html.contains("javascript:"),
+            "JavaScript URLs should be removed"
+        );
+
+        let actual_html = result.html.trim();
+        let expected_html = expected_html.trim();
+        assert_eq!(
+            actual_html, expected_html,
+            "XSS safety output does not match expected fixture"
+        );
     }
 }
diff --git a/docs/roadmap.md b/docs/roadmap.md
index 7f0d875..cc11d9f 100644
--- a/docs/roadmap.md
+++ b/docs/roadmap.md
@@ -94,7 +94,7 @@ A "thorough" Markdown pipeline: deterministic HTML, structured metadata, and sou
       - Outline JSON match
       - Sourcepos presence for block nodes
 
-## Editor MVP (React): CodeMirror 6 + Markdown language + Elm integration
+## Editor (React)
 
 A robust text editor that cooperates with Elm state management (no "hidden state surprises").
 
@@ -116,6 +116,8 @@ A robust text editor that cooperates with Elm state management (no "hidden state
    - `Msg::SaveRequested`
    - `Msg::SaveFinished`
    - `Msg::DocOpened`
+5. Oxocarbon Dark & Light themes
+6. Testing library tests
 
 ## Preview renderer + scroll/selection sync (editor ↔ rendered HTML)
 
diff --git a/fixtures/markdown/basic.html b/fixtures/markdown/basic.html
new file mode 100644
index 0000000..4ed380e
--- /dev/null
+++ b/fixtures/markdown/basic.html
@@ -0,0 +1,39 @@
+<h1 data-sourcepos="1:1-1:15">Test Document</h1>
+<p data-sourcepos="3:1-3:52">This is a paragraph with <strong data-sourcepos="3:26-3:33">bold</strong> and <em data-sourcepos="3:39-3:46">italic</em> text.</p>
+<h2 data-sourcepos="5:1-5:12">Section 1</h2>
+<p data-sourcepos="7:1-7:18">Here is some code:</p>
+<pre data-sourcepos="9:1-13:3"><code class="language-rust">fn main() {
+    println!(&quot;Hello, world!&quot;);
+}
+</code></pre>
+<h3 data-sourcepos="15:1-15:14">Subsection</h3>
+<ul data-sourcepos="17:1-19:8">
+<li data-sourcepos="17:1-17:8">Item 1</li>
+<li data-sourcepos="18:1-18:8">Item 2</li>
+<li data-sourcepos="19:1-20:0">Item 3</li>
+</ul>
+<h2 data-sourcepos="21:1-21:12">Section 2</h2>
+<table data-sourcepos="23:1-26:16">
+<thead>
+<tr data-sourcepos="23:1-23:16">
+<th data-sourcepos="23:2-23:7">Name</th>
+<th data-sourcepos="23:9-23:15">Value</th>
+</tr>
+</thead>
+<tbody>
+<tr data-sourcepos="25:1-25:16">
+<td data-sourcepos="25:2-25:7">A</td>
+<td data-sourcepos="25:9-25:15">1</td>
+</tr>
+<tr data-sourcepos="26:1-26:16">
+<td data-sourcepos="26:2-26:7">B</td>
+<td data-sourcepos="26:9-26:15">2</td>
+</tr>
+</tbody>
+</table>
+<ul data-sourcepos="28:1-29:21">
+<li data-sourcepos="28:1-28:20"><input type="checkbox" checked="" disabled="" /> Completed task</li>
+<li data-sourcepos="29:1-29:21"><input type="checkbox" disabled="" /> Incomplete task</li>
+</ul>
+<p data-sourcepos="31:1-31:22"><del data-sourcepos="31:1-31:22">Strikethrough text</del></p>
+<p data-sourcepos="33:1-33:40">Visit <a data-sourcepos="33:7-33:25" href="https://example.com">https://example.com</a> for more info.</p>
diff --git a/fixtures/markdown/basic.md b/fixtures/markdown/basic.md
new file mode 100644
index 0000000..b9d0ee5
--- /dev/null
+++ b/fixtures/markdown/basic.md
@@ -0,0 +1,33 @@
+# Test Document
+
+This is a paragraph with **bold** and *italic* text.
+
+## Section 1
+
+Here is some code:
+
+```rust
+fn main() {
+    println!("Hello, world!");
+}
+```
+
+### Subsection
+
+- Item 1
+- Item 2
+- Item 3
+
+## Section 2
+
+| Name | Value |
+|------|-------|
+| A    | 1     |
+| B    | 2     |
+
+- [x] Completed task
+- [ ] Incomplete task
+
+~~Strikethrough text~~
+
+Visit https://example.com for more info.
diff --git a/fixtures/markdown/basic.outline.json b/fixtures/markdown/basic.outline.json
new file mode 100644
index 0000000..c55fd16
--- /dev/null
+++ b/fixtures/markdown/basic.outline.json
@@ -0,0 +1,14 @@
+{
+  "title": "Test Document",
+  "outline": [
+    { "level": 1, "text": "Test Document" },
+    { "level": 2, "text": "Section 1" },
+    { "level": 3, "text": "Subsection" },
+    { "level": 2, "text": "Section 2" }
+  ],
+  "word_count": 42,
+  "task_items": {
+    "total": 2,
+    "completed": 1
+  }
+}
diff --git a/fixtures/render/xss-safety.html b/fixtures/render/xss-safety.html
new file mode 100644
index 0000000..5bc8a06
--- /dev/null
+++ b/fixtures/render/xss-safety.html
@@ -0,0 +1,6 @@
+<h1 data-sourcepos="1:1-1:10">XSS Test</h1>
+<p data-sourcepos="3:1-3:57">This tests that raw HTML is properly escaped or filtered.</p>
+<!-- raw HTML omitted -->
+<p data-sourcepos="7:1-7:32">&lt;img src=x onerror=alert('XSS')&gt;</p>
+<p data-sourcepos="9:1-9:46"><!-- raw HTML omitted -->Click me<!-- raw HTML omitted --></p>
+<!-- raw HTML omitted -->
diff --git a/fixtures/render/xss-safety.md b/fixtures/render/xss-safety.md
new file mode 100644
index 0000000..c51fe49
--- /dev/null
+++ b/fixtures/render/xss-safety.md
@@ -0,0 +1,11 @@
+# XSS Test
+
+This tests that raw HTML is properly escaped or filtered.
+
+<script>alert('XSS')</script>
+
+<img src=x onerror=alert('XSS')>
+
+<a href="javascript:alert('XSS')">Click me</a>
+
+<style>body { background: red; }</style>